1. Field of the Invention
The present invention relates to a method of and apparatus for recording data on an optical recording medium, and more particularly, to a method and apparatus in which digital data is recorded on an optical disc by forming a mark on the optical disc.
2. Description of the Related Art
Data are recorded on an optical disc which is one type of optical recording media, in a form of a mark on a track formed on the optical disc. A mark is formed as a pit in a read-only disc, such as a Compact Disc-Read Only Memory (CD-ROM) and a Digital Versatile Disc-Read Only Memory (DVD-ROM). In a recordable disc, such as a CD-R/RW and a DVD-R/RW/RAM, a phase-change film which is changed into a crystalline phase or an amorphous phase is formed on a recording layer, and a mark is formed by a phase change of the phase-change film.
Methods of recording data can be divided into a mark edge recording method and a mark position recording method. According to the mark position recording method, a signal of an amplitude of a detected Radio Frequency (RF) signal is changed from negative to positive or from positive to negative at a location on which a mark is recorded. According to the mark edge recording method, the signal of the amplitude of the detected RF signal is changed from negative to positive or from positive to negative at both edges of the mark. Therefore, recording the edges of the mark is an important factor in improving quality of a signal reproduced from the optical disc.
However, in a disc on which the phase-change film is coated, it is shown that a shape of a trailing edge of the mark recorded according to a prior art recording method changes according to a length of the mark or an interval between the marks, i.e., a space. That is, the trailing edge of the mark is formed greater than a leading edge of the mark such that recording/reproducing characteristics of the disc are degraded. If a recording mark is relatively long, the recording/reproducing characteristics are more degraded.
FIGS. 1A-1E are reference diagrams of recording waveforms (a), (b), and (c) to record a Non Return to Zero Inverted (NRZI) data signal according to the prior art. The recording waveform (a) is used for recording the NRZI data signal on a DVD-RAM, the recording waveforms (b) and (c) are for a DVD-RW. Here, T denotes a cycle of a reference clock. According to the mark edge recording method, a high level of NRZI data is recorded as a mark and a low level of NRZI data is formed as a space. A portion of the recording waveform used in recording the mark is referred to as a recording pattern, and another portion of the recording waveform used in forming the space (in erasing the mark) is referred to as an erase pattern. The prior art recording waveforms (a), (b) and (c) use a multi-pulse as the recording pattern, and a power of the erase pattern is maintained constant in a predetermined DC level for an interval E as shown in FIG. 1E.
Since the DC level of the erase pattern included in the prior art recording waveform is maintained constant for a predetermined period of time, 0˜200° C. heat is continuously applied to a corresponding area to form the space. Therefore, if recording is repeatedly performed, a shape of the mark is degraded and distorted such that the recording/reproducing characteristics of the optical disc are degraded. In particular, a development toward a high density and a high line speed for recording more data on the optical disc makes the clock cycle T shorter, and therefore a heat interference between pulses forming the recording waveform increases to cause more degradation of the recording/reproducing characteristics of the optical disc.
Meanwhile, in the prior art, the different recording waveforms are used according to the kinds of the optical discs and specifications, such as DVD-RAM and DVD-RW, because characteristics of recording films of the optical discs are different. In particular, due to the fact that the different recording waveforms should be used for each kind of the optical discs, a problem occurs in manufacturing a multi-drive which can record/reproduce all specifications of the optical discs because the multi-drive should accommodate a variety of the different recording waveforms. The problem causes an increase in cost.